This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project is part of the effort to define the heparin sulfate (HS) binding site of Slit and Robo, proteins involved in the development of the nervous system and the vasculature. Specifically, the aim of this project is to determine the minimum size of HS required for binding to these proteins.